Senate Majority Leader Mitch McConnell, R-Ky., joined at left by Sen. John Thune, R-S.D., speaks to reporters about the political battle for confirmation of President Donald Trump's Supreme Court nominee, Brett Kavanaugh, following a closed-door GOP policy meeting, at the Capitol in Washington, Tuesday, Oct. 2, 2018. (AP Photo/J. Scott Applewhite)

The Kentucky Republican's remarks on the Senate floor were an extended version of a message party leaders have delivered since last week. That's when the GOP began accusing Democrats of condoning "mob rule" after raucous demonstrators opposing Brett Kavanaugh's Supreme Court nomination harangued GOP lawmakers at the Capitol last week. Some Republicans said they received death threats.

McConnell described protesters "literally storming the steps of the Capitol and the Supreme Court," confronting Republicans at restaurants and shouting from the Senate visitors' galleries during last week's debate and vote on Kavanaugh.

"Only one side was happy to play host to this toxic fringe behavior," McConnell said. "Only one side's leaders are now openly calling for more of it. They haven't seen enough. They want more. And I'm afraid this is only Phase One of the meltdown."

He added: "We will not let mob behavior drown out all the Americans who want to legitimately participate in the policy-making process.

McConnell's comments come less than four weeks from elections in which Democrats are seen as having a strong chance at capturing control of the House but weaker odds of winning a majority in the Senate.

Until the rancorous debate over Kavanaugh — he denied accusations by three women of 1980s sexual misconduct — polls suggested that GOP supporters were far less motivated to vote than Democrats, who are ardently opposed to President Donald Trump. Republicans have said the rowdy opposition to Kavanaugh has given conservative voters a new enthusiasm. McConnell has called it a political gift.

The GOP rhetorical offensive also represents a flipping of the recent script, in which Democrats have accused Trump of intensifying divisions with nationalistic and at times racist appeals to his conservative base and personal attacks on political enemies.

Almost a decade ago, Democrats also assailed the Tea Party, grassroots conservatives who rallied against President Barack Obama's health care law and who angrily shouted down lawmakers at town hall meetings.

On Thursday, McConnell cited recent statements by 2016 Democratic presidential candidate Hillary Clinton and former Attorney General Eric Holder. And he pointedly noted that these activities followed last year's shooting of GOP lawmakers at a morning baseball practice by "a politically crazed gunman."

James Hodgkinson, who was killed at the scene by officers, was infuriated by President Donald Trump's election, his widow has said.

Clinton said on CNN this week that "civility can start again" after Democrats capture the House or Senate in next month's elections.

In a video purportedly shot at a recent campaign event in Georgia, Holder says, "When they go low, we kick them," paraphrasing former first lady Michelle Obama, who famously said during the 2016 campaign, "When they go low, you go high."